The subject matter disclosed herein relates to a helicopter blade active trailing edge flap and, more particularly, to a flexbeam hinge for an active trailing edge flap of a helicopter blade.
In most helicopters, a main rotor is disposed at a top portion of the helicopter fuselage and a tail rotor is disposed at a rear of the fuselage. The main and tail rotors are formed of multiple blades and cooperatively operate to provide uplift, thrust and control for the helicopter by rotating at high speed. The blades may include actively controlled trailing edge flaps that can be pitched around a pitching axis defined along the span of the corresponding blade for added control.
Typically, the active control of each of the trailing edge flaps of a helicopter is provided by bearing designs in which a rotating shaft is supported by ball or spherical bearings. The actively controlled trailing edge flaps may be actuated at least once and, in some cases, up to five times per revolution of the rotor blade. As such, the bearings tend to exhibit large wear rates and a constant need for lubrication due to their sliding contact with nearby components. These large wear rates often lead to frequent replacement of the bearings and high associated costs. In addition, the bearings lead to frictional moments in the bearing designs that must be overcome by pitch control systems especially wear high frequency pitching is required.